A healthy diet, exercise and certain medications are the
cornerstones of diabetes prevention and treatment.
However, some herbs and supplements may also have potential
Interestingly, many of them have been shown to have
anti-diabetic properties, including lowering blood sugar and
improving blood lipids and insulin sensitivity.
This is a list of the most promising herbs and supplements for
Turmeric is an herb that gives curry its yellow color. It
contains a compound called curcumin, which has several
medicinal properties, including anti-diabetic effects.
Studies have shown that curcumin has the ability to lower
blood sugar levels. One recent study found that taking just
300 mg a day of highly purified curcuminoids decreased blood
sugar levels by almost 18% (1, 2).
Another study of more than 200 prediabetics found that taking
1.5 grams of curcumin for 9 months improved beta-cell function
and prevented the development of type 2 diabetes during the
Bottom Line: Turmeric is the spice that
gives curry its yellow color. It contains an active compound
called curcumin, which may lower blood sugar and decrease the
risk of developing diabetes.
is a popular spice used in cooking and home remedies.
It may also improve some diabetes symptoms.
One study of 88 participants found that taking 3 grams of
ginger daily for eight weeks reduced fasting blood sugar and
HbA1c levels, which are a measure of average blood sugar levels
over the past 2–3 months (9).
Lastly, evidence also suggests that the active compounds found
in ginger can help prevent changes in proteins caused by high
blood sugar. These changes can damage cells, nerves and blood
vessels (16, 17).
Bottom Line: Ginger is a medicinal and
culinary plant that may help moderate blood sugar levels,
fight inflammation and prevent some negative outcomes of
Cinnamon is a well-known supplement for diabetes. However,
the evidence for its use is conflicting.
Many lab studies have shown that cinnamon may help improve
insulin resistance, lower the absorption of glucose after a
meal and fight inflammation. However, many large reviews of
studies in humans have not found consistent results (18, 19, 20, 21).
Some studies show no significant effects, while others find
improvements in fasting blood sugar, total cholesterol, “bad”
LDL cholesterol and “good” HDL cholesterol.
Another problem with recommending cinnamon as a supplement for
diabetes is that the two main types of cinnamon — Ceylon
and Cassia — have varying effects. Moreover, neither has
been studied well.
Some evidence suggests that Cassia cinnamon may be more
effective at lowering blood sugar levels, and most studies in
humans have used Cassia cinnamon or not specified which type
was used (26).
However, Cassia cinnamon has a high content of coumarin, which
has the potential to cause liver damage if taken in excess.
Although current studies have not found this effect, they have
been too small and too short to say for sure (27).
Therefore, if cinnamon is used as a supplement, Ceylon cinnamon
is the safer choice.
Bottom Line: Cinnamon may improve blood
sugar and blood lipid levels. However, the evidence is
conflicting. It’s also important to choose the right form of
Unfortunately, only a few studies have explored these effects
in humans. Nevertheless, the results are encouraging.
One study in type 1 and type 2 diabetics found that simply
consuming 100 grams of raw, red onion caused a significant
decrease in high blood sugar levels in both types of patients
when consumed with a meal that contained sugar (31).
While the evidence is only preliminary, adding onion to
your diet appears to be an easy way to help keep your blood
sugar levels under control.
Bottom Line: The use of onion to treat
diabetes has not been extensively studied in humans. However,
some evidence suggests that adding onion to your diet may
help keep your blood sugar in check.
5. Black Seed or Black Curry
Black seed, or black curry (Nigella
sativa), is the seed of a flower that has a history of use
in traditional medicine.
A recent review of 23 human studies including over 1,500
participants found that black seed significantly reduced
fasting blood sugar and HbA1c in more than half of the studies
However, more research is necessary to confirm these effects
and determine the appropriate dosage.
Bottom Line: Black seed or black curry is a
seed that shows promise in improving blood sugar and blood
lipid levels, as well as protecting the heart and liver from
Fenugreek is an
herb often used in cooking and home remedies for many
Studies on the use of fenugreek in diabetics have not been
consistent, but a large review found that fenugreek
significantly decreased fasting blood sugar, post-meal blood
sugar, average blood sugar over 2–3 months (HbA1c) and
Other reviews have also found that fenugreek helped lower blood
sugar, but just how much of an impact it has is not clear. One
review found that fenugreek helped lower blood sugar by 17
mg/dl on average, which is relatively small (48, 49, 50).
Interestingly, fenugreek may help prevent diabetes in the first
place. Another recent study found that daily supplementation of
fenugreek over three years significantly reduced the number of
people who developed diabetes during the study (51).
However, an upset stomach may be a side effect.
Bottom Line: Results have been inconsistent,
but fenugreek may improve several different measures of blood
sugar or even reduce the risk of developing diabetes.
However, side effects may be a concern.
7. Aloe Vera
Aloe vera is a common house and garden plant that is also well
known for its
health benefits, perhaps most famously for soothing the
pain of a sunburn.
However, it’s currently being extensively studied for other
uses as well, including as an oral supplement to improve
symptoms of diabetes.
Reviews of recent studies have found that aloe vera can
significantly reduce fasting blood sugar.
One study found that aloe vera reduced HbA1c, a measure of
average blood sugar over the past several months, by 1.05%,
which is very promising (52).
Bottom Line: Several reviews have found that
aloe vera can help lower high blood sugar. However, more
studies are needed to confirm its effectiveness and safety.
Berberine is a supplement derived from plants. It has long
been studied for its anti-diabetic effects.
In one three-month study of 36 patients, berberine supplements
were nearly as effective as metformin, a diabetes medication
that helps control blood sugar levels.
In fact, berberine decreased HbA1c from 9.47% to 7.48%.
Interestingly, less than 7.0% is well-controlled for diabetics
and less than 6.0% is considered normal. It also decreased
fasting blood sugar by 36% and post-meal blood sugar by 44%
Unfortunately, berberine is very poorly absorbed, meaning the
dosage is usually rather high. In one study, up to 34.5% of
patients experienced side effects, including diarrhea,
flatulence and stomach pain (57).
However, berberine appears to be effective and scientists are
continuing to research ways to improve its ability to be
Bottom Line: Berberine is a supplement that
appears to be effective at lowering high blood sugar, blood
lipid levels and inflammation. However, it is poorly absorbed
and side effects may be common.
9. Bilberry, Blueberry and Whortleberry
Several berries from the Vaccinium family, such as
blueberries and whortleberries, may help fight symptoms of
Large observational studies have found that consuming berries
is associated with a lower risk of developing type 2 diabetes
A few studies in humans have also found promising results.
One study found that taking whortleberry extract three times
per day for two months lowered fasting blood sugar by 16.3%,
post-meal blood sugar by 13.5% and HbA1c by 7.3% (65).
Another study found that bilberry supplements significantly
reduced post-meal blood sugar (66).
Also, drinking a blueberry smoothie for six weeks was found to
improve insulin sensitivity in people with prediabetes
While the evidence about berries and diabetes is still very
preliminary, it does seem promising.
Bottom Line: A few small studies have found
that berries from the Vaccinium family can help
lower several measures of blood sugar levels. However, more
studies are needed.
Chromium supplements for diabetes are
Unfortunately, most of the studies conducted in humans have
been small or had significant design flaws, making their
results unreliable (48).
Chromium may help lower blood sugar in people with diabetes,
but more high-quality studies are needed to confirm its
effectiveness and determine the proper form and dosage.
Bottom Line: Some evidence shows that
chromium is effective at lowering blood sugar levels.
Unfortunately, many of these studies were small and had
design flaws, so stronger evidence is needed.
Researchers have recently learned that magnesium
may play a role in diabetes.
While it’s known that high levels of insulin can cause blood
magnesium levels to decrease, that doesn’t mean that
supplementing with magnesium is beneficial.
However, one review including over 600,000 participants found
that people who consumed the highest amounts of magnesium from
their diets had a 17% lower risk of developing diabetes than
those who consumed the least magnesium (71).
The same study found that for every 100-mg increase in dietary
intake of magnesium per day, the risk of diabetes decreased by
up to 13%.
This evidence is only observational, so it alone cannot prove
that supplementing or increasing dietary intake of magnesium is
beneficial. But it does demonstrate the importance of getting
enough magnesium from your diet.
Furthermore, several reviews have also examined the effects of
However, it’s not clear if magnesium supplements are beneficial
for all people who have or are at risk of diabetes. It may only
be beneficial to those who are not getting enough magnesium
from their diet in the first place (72).
Bottom Line: Getting enough magnesium is
important for controlling blood sugar levels in diabetics.
However, magnesium supplements may only benefit those who
have low magnesium blood levels.
Other Herbs and Supplements
Countless herbs and supplements have been studied for their
possible benefits for diabetes, but most only have preliminary
evidence behind them.
Vitamin C is an antioxidant that may fight inflammation
and improve insulin sensitivity. However, the evidence is
very contradictory, and it’s unclear if it has any real
benefit (74, 75, 76, 77).
Coenzyme Q10: Coenzyme Q10, or ubiquinone, is an enzyme
involved in the production of energy. Some preliminary
evidence suggests it may fight oxidative damage and protect
kidney and nerve function in diabetics (78, 79, 80).
Coriander: Coriander, or cilantro, is a
common herb. In the lab, coriander extract has inhibited
enzymes that help break down complex carbs into sugars. It
may also have antioxidant and lipid-lowering effects
(81, 82, 83).
Rosemary: Rosemary is a popular culinary
herb with a wide range of health properties. It may benefit
diabetics, but all studies to date have been conducted in
test tubes or animals (84, 85, 86).
Garlic has well-documented anti-diabetic effects,
including lowering high blood sugar and fighting
inflammation. However, most of these effects have only been
studied in animals (87, 88, 89, 90).
Bottom Line: Many more herbs and
supplements, including garlic, coriander and vitamin C, have
properties that might be useful for diabetics. However, they
have not yet been studied enough in humans.
Take Home Message
Many herbs and supplements may benefit those with or at risk of
diabetes. However, most need to be better studied in regards to
safety, effectiveness and dosage.
While none of these options should be used to replace diet and
lifestyle changes or medications, they may help improve some
symptoms or risk factors for diabetics.
If you’re thinking about trying herbs or supplements, talk to
your doctor to determine how they can fit into your treatment
plan. This is especially important if you are currently taking
medications, which may need to be adjusted.
Lastly, because the US supplement market is not well regulated,
do your research to ensure that you’re buying from a reputable