Also known as vitamin B3, niacin is a popular vitamin associated with promoting human health. It is also one of the essential human nutrients, making it particularly relevant to any discussion of health.
However, because the RDA of niacin is so low, most people easily achieve the required level of niacin from diet alone.
This means that niacin deficiency is rare, and normally only occurs in people suffering from alcoholism.
Preventing niacin deficiency is only one of the uses of this compound, and niacin is frequently consumed at levels far above the RDA in order to combat high levels of LDL in the blood and to decrease the amount of triglycerides in the body.
Much of the discussion about niacin has focused on its relationship to cholesterol, specifically concerning HDL cholesterol.
That topic often ends with the question, does niacin raise HDL?
As with most questions about health, the answer is never as simple as the question.
However, from the research and my own personal experience, the answer is yes, although that may not necessarily be true for everyone.
HDL, LDL and Cholesterol
Cholesterol is always a complex topic and I’m just going to skim it in this particular discussion.
The terms HDL and LDL stand for high-density lipoprotein and low-density lipoprotein, respectively. The terms are used to describe cholesterol, but that isn’t strictly true. Instead, HDL and LDL are the compounds that carry cholesterol in the bloodstream.
In general, LDL is considered to be the bad form of cholesterol and it tends to be associated with increased risk of heart disease. In contrast, HDL is considered to be the good type of cholesterol, and is associated with being healthy.
In fact, increasing HDL may play a role in protecting the body from heart disease and stroke. Additionally, low HDL cholesterol is a risk factor in heart disease development (1).
Generally speaking, improving health and decreasing the risk of cardiovascular disease involves increasing the level of HDL while also decreasing LDL levels.
However, changing eating habits is often not sufficient to lower the level of LDL cholesterol, and this can be the driving force behind decisions to use medication or supplements like niacin.
There is a lot of discussion in the medical and in the scientific fields about cholesterol and what its specific implications for health are.
In the past, there has been an emphasis on watching the cholesterol in our food, which has led to people trying to lower their cholesterol through the food they eat. However, as I mentioned before, this is not always enough.
In fact, there is growing recognition that because of the way that our bodies produce cholesterol, our diets have a minimal impact on our cholesterol levels. For example, the site Heathline highlights why dietary cholesterol doesn’t matter for most people and Chris Kresser offers details on the actual connection between diet and heart disease.
Niacin, HDL and Heart Disease Risk
HDL and Heart Disease Risk
The relationship between HDL and the risk of heart disease is an area that continues to be researched.
One research study used a genetic analysis approach to look at the relationship between HDL-C (that is, the cholesterol actually bound to HDL) and heart disease.
The outcomes of the study did indicate that triglycerides could have an impact on heart disease risk, but the authors were unable to establish whether or not HDL-C played a causal role (2).
Another study used a meta-analysis to look that the relationship between HDL levels and cardiovascular disease.
The authors found that overall there was not enough data to suggest that increased levels of HDL could reduce the risk of heart disease, deaths from heart disease and overall heart disease levels (3).
One interesting area is genetic influencers of HDL levels.
As with many aspects of our bodies, HDL is influenced by our genetics as well as foods that we eat and medications that we take. This has significant implications for HDL levels overall, partly because it means that there will be differences between individuals, regardless of the similarities in their approaches.
One research study found that genetic HDL levels had different implications.
In particular, they found that raising HDL through genetic mechanisms did not have the same protective effect against heart attacks as raising HDL through other means (4).
That outcome is important as it indicates that the approach of treating all HDL as the same may be flawed.
There are many more research studies into HDL and heart disease, but there continue to be significant inconsistencies between studies, particularly in terms of their outcomes and the measures they use.
Many large-scale studies have failed to find the expected relationship between HDL-C and heart disease (5).
This makes it difficult to conclusively determine what role HDL has on heart disease.
The Impacts of Niacin
One large scale consideration of the relationship between niacin, HDL and heart disease was a meta-analysis conducted in 2014. In their meta-analysis, the authors considered outcomes for 117,411 patients across 39 different trials.
The authors did not find any significant roles of niacin for heart disease mortality, for non-fatal heart attacks (in patients receiving statins only) or on all-cause mortality.
Interestingly, the authors did find that niacin was associated with a decreased risk of heart attacks that did not cause death, but only in those patients not taking statins (6).
A second significant study was the THRIVE study, which involved 11,000 Chinese patients.
The authors of this study found that supplementing with niacin did not significantly reduce heart disease risk (7).
A similar outcome was found for a second key study into the area, known as the AIM-HIGH trial (8).
So, does this mean that niacin is useless?
In reality, it’s hard to say.
Many studies on the topic have been fundamentally flawed for testing the impacts of niacin, making it difficult to know what impact the supplement actually has.
There has also been a decent amount of research that has highlighted on the effectiveness of niacin (9,10,11,12), and in some circles, niacin is considered an effective approach for cholesterol management and is regularly used (13).
These apparent contradictions make niacin a challenging topic and there is certainly no consensus in the literature about how effective or not effective it is.
Limitations of Research
While the research studies have shown little benefit of supplementing with niacin, it’s important to note that these studies were limited.
In particular, the two largest studies (THRIVE and AIM-HIGH) into this area both added niacin to statin treatments.
For example, in the meta-analysis studies, a total of 35,301 patients were involved in studies that involved niacin as an outcome measure. Of those patients, 30,310 were in studies that also included statins.
This meant that only 4,991 people were in studies that did not use statins and many of those were small studies (14).
That is additionally problematic because the small sample sizes make it difficult to assess whether or not any relationship is present.
This is an unusual approach because both niacin and statins can have influences on cholesterol.
Additionally, that design isn’t a very good reflection of real life use.
Most people who turn to supplements to control issues like cholesterol are people that are trying to avoid the use of drugs like statins. At the same time, people who rely on prescribed medications are unlikely to choose supplements unless those are also prescribed.
Overall, the studies simply did not act as very good tests of how effective niacin actually is in increasing HDL. After all, it’s very possible that the actions of statins had some impacts on what niacin was able to do.
Another factor is that when people already have low LDL, a high level of HDL isn’t as important.
In fact, one meta-analysis found that niacin was associated with a significant decrease in non-fatal heart attacks, but only in cases where statins were not being taken (15).
These research studies also didn’t focus on niacin on its own. Instead, they also included the drug laropiprant, which is used to decrease the niacin flush.
Taking that type of approach is always problematic because it limits how much information the study offers. In particular, doing this means that there is no real way to know whether laropiprant was having an impact on the outcomes of niacin (16).
An additional problem is that interest and research into niacin have decreased significantly as a result of the outcomes of those two studies.
As a result of this situation, there simply isn’t enough information to know whether supplementing with niacin (independently of statins) has a significant effect on HDL levels.
A final note is that most of the studies into niacin and cholesterol have ignored HDL subtypes. This is actually a really important area that is starting to be recognized more.
In particular, there are multiple sizes of HDL particles. Five different sizes have been found. From largest to smallest these are 2a, 2b, 3a, 3b and 3c. The larger sizes are the most effective at removing cholesterol, making them the most desirable types of HDL (17,18).
At the same time, the smaller particles are more effective for other areas of health, including anti-inflammatory and antioxidant actions (18).
The HDL subclasses have been an area of significant research and we continue to learn more about them.
For example, some research has shown that some HDL particles can become overloaded with cholesterol and this has been associated with the development of carotid atherosclerosis. This pattern may be why interventions for raising HDL levels have not always been successful at decreasing heart disease risk (19).
Conventional measures of cholesterol do not take the subtypes of HDL into consideration. Yet, these subtypes may be critical for understanding the relationship between HDL and disease. They are also highly relevant for understanding individual risk and can provide much more information than just HDL levels (20).
Realistically, to fully understand the role of niacin and HDL cholesterol on heart disease risk, a much greater focus on these subtypes and on ways of measuring HDL cholesterol are needed.
This is just as true for looking at the levels of risk that individuals face. It is clear that simply looking at HDL levels does not provide sufficient information, but HDL subtypes may be much more relevant (21).
Overall, this suggests that answers in this particular area are very limited, making it much more difficult to recommend for or against niacin or even for or against practices of raising HDL.
Instead, it is still possible that HDL and/or niacin may be relevant for some subgroups, but the research simply has not focused on this area enough to prove or disprove whether this is the case.
Personally, I feel that there is enough evidence to support working to increase one’s HDL levels and niacin is a tool that I have personally found to be effective at doing just that.
The Value of Niacin
The simple answer to the question does niacin raise HDL is yes, it does.
But, as I mentioned before, the answer to this type of question is never simple.
For one thing, there is currently not enough evidence to show whether increasing HDL levels actually decreases cardiovascular disease risk (22).
At the same time, most studies have been so limited that it’s hard to work out what effects are and are not occurring.
For example, the different subtypes of HDL, the way these subtypes are distributed for individuals, differences in quality and quantity of HDL and the ratio of HDL to LDL levels are all factors that can affect research and outcomes surrounding HDL.
It is challenging, if not impossible, for research studies to effectively control for all of these areas.
Why Does Niacin Cause Flushing?
One interesting thing about niacin is its ability to cause a flush.
This is pretty unusual because most nutritional supplements don’t have any immediately visible impacts on the body.
In fact, with other supplements, it can sometimes be hard to tell whether you even took them or not.
With niacin, this isn’t the case.
Instead, many people who take the vitamin experience a hot flushing sensation, where their face will often become red and they may also feel hot and sweaty.
While the flush can seem uncomfortable, it isn’t an allergic reaction.
Instead, it is a side effect of the way that niacin works on the body (26).
In particular, it happens because niacin has an impact on key receptors in the body, which contribute to the flushing reaction.
Most people develop a tolerance for the flushing relatively fast, so the same dose of niacin will tend to cause less flushing as a person takes it (27).
Because some people find the flush uncomfortable, there has been a focus on finding ways to either decrease its severity or prevent it from occurring altogether.
Indeed, researchers argue that the flush is a limiting factor in the effective use of niacin, as some people can choose not to take niacin because of this flushing (28).
One approach for reducing flushing is for people to take NSAIDs, particularly aspirin, around half an hour before taking niacin. This can significantly reduce the flushing effect (29).
The formulation of the niacin can also play a role.
In particular, immediate-release niacin tends to cause a stronger flush. In contrast, extended-release niacin can be used as a way to get the benefits of niacin with less severe flush symptoms (30,31).
The extended-release version reduces the flush by having a slightly different mechanism (32). This different mechanism may have some impact on the outcomes of niacin, but researchers tend to highlight its advantages over any potential differences (33,34).
Even then, some degree of flushing occurs in many cases when niacin is taken at clinically relevant doses (35).
While the flushing that niacin causes isn’t anything to be concerned about, there are still safety considerations.
Minor side effects from niacin can include dizziness, stomach upset and gas although these will often become less significant as a person builds up a tolerance (36).
These side effects are one reason that many sites recommend taking things slowly and not moving too fast while the niacin flush is occurring.
When people are taking relatively high doses of niacin (above 3 grams per day), there is the risk of more serious side effects.
These include liver problems, gout, high blood sugar, as well as a number of other side effects (37).
Niacin also has the potential to make allergies worse, because it produces histamine, which plays a role in allergy symptoms (38).
There has also been one case where a low dose niacin was associated with the development of vision loss (39). However, this is the only reported case of such an outcome, suggesting that it may be an abnormality.
Regardless, if you have a medical condition or take medications, it is important to seek medical advice before starting to take niacin.
This is particularly true if you plan on taking more than 3 g of niacin per day.
Depending on your health conditions and aims, it may still be desirable to take more than 3 g daily, but a physician will be able to help you make that decision.
Despite the potential side effects from niacin, there really is enough evidence to suggest that it is a viable approach for increasing HDL.
Nevertheless, it is worth noting that one specific form of extended release niacin was associated with health issues. This was a niacin/laropiprant combination, and the form has since been taken off the market (40,41).
However, the negative outcomes were the result of the laropiprant combination, rather than the niacin itself.
Does Niacin Raise HDL?
When used correctly, both medication and supplements do have the ability to promote improved health and wellbeing. Nevertheless, at the same time, anything like this will tend to have complex impacts on your body, often resulting in side effects or interactions.
In most cases, like vitamin D, there is very solid research backing up that supplement.
Niacin is a little bit different.
With niacin, the research isn’t as clear cut. While many people do swear by niacin, there are also large-scale studies that suggest niacin isn’t all that powerful. Despite those outcomes, it seems too soon to claim that niacin isn’t worth the effort.
In this case, the large-scale research was flawed, and the results of that research certainly don’t apply to the entire population. For example, patients who are already on statins and those who should be on statins, probably don’t need to be on niacin as well.
When it comes to niacin, it may be that the drug is suited for specific people, rather than the general population.
After all, the point of HDL cholesterol is to help move cholesterol out of that body. That’s largely irrelevant for people who already have low LDL.
Instead, that suggests niacin may be a good choice for people who want to lower their cholesterol but who don’t want to be on statin medications.
At the end of the day, using niacin may be a good choice if you want to increase your HDL levels, especially in situations where you want to avoid the use of statin medications.
However, when you are deciding whether to start using niacin, it is important to look at your own lifestyle and preexisting conditions, as niacin will not be right for everyone.
Likewise, you should keep niacin’s safety profile in mind and talk to your physician before making any significant changes.
As research continues into the HDL subclasses and their unique profiles and benefits, we may well learn more about the benefits of niacin to increase HDL levels and to reduce the risk of heart disease. However, the research isn’t at that stage yet, and there is still much that we do not know.