Squalene is a natural substance found most commonly in olive oil. It is praised for its anti-cancer and skin-protecting effects. However, squalene may also be beneficial in Parkinson’s disease, lower cholesterol levels, and act as an antioxidant. Learn more about it in this post.
What is Squalene?
Squalene is abundant in both olive oil and shark liver oil [R].
Squalene has some beneficial properties when consumed either from food or as a supplement. These include potential anticancer effects, protective and moisturizing role in the skin, antioxidant activity and it may even improve the immune response to vaccines.
Squalene vs. Squalane
It’s important not to confuse squalene with squalane.
Squalene is broken down into squalane in the body by certain enzymes (squalene epoxidase, also known as squalene monooxygenase) [R].
Squalane is also common in cosmetic products, but it differs from squalene in its health effects [R].
Natural Sources and Supplements
There are multiple natural sources of squalene and supplements of the following oils can be purchased:
- Olive oil: Olive oil is a common source of squalene. Olive oil contains about 3.9 to 9.6 grams of squalene per liter [R].
- Shark liver oil: Shark liver oil is the richest known source of squalene. Squalene levels are high in the fatty tissues of sharks.*
*Cancer researchers once thought that squalene was the reason that sharks seemingly did not get cancer. Although this has been shown to be false, as sharks do indeed get cancer, squalene still may play an important protective role.
- Other sources: Squalene is also found in palm oil, wheat-germ oil, amaranth oil, and rice bran oil [R].
- Squalene is also produced naturally within the body and is a precursor to cholesterol.
Mechanisms of Action
- Being a precursor to the synthesis of cholesterol and steroid hormones like testosterone and estrogen
- Inhibiting HMG-CoA reductase, which blocks ras pathways involved in cancer growth
- Increasing production of collagen (type 1 procollagen), reducing UV ray damage and wrinkles
- Supporting pro-hydration processes within the skin, acting as a natural moisturizer
- Reducing double-stranded breaks in DNA, lowering DNA damage
- Activating enzymes involved the Krebs cycle and oxidative phosphorylation, along with increases detoxing of the body (glutathione-dependant)
- Increasing fat metabolism by activating PPARα
- Protecting against oxidative damage in the striatum
- Possibly increasing healthy cholesterol levels (HDL)
Health Benefits of Squalene
1) Squalene Protects the Skin
Squalene is found in the outer layer of the skin and plays a role in protecting against UV radiation [R].
Without sufficient squalene, UV rays can induce inflammation in the skin [R].
In 40 women over the age of 50, squalene supplementation given for 90 days reduced redness and improved collagen activity at low doses (13.5 grams per day). At higher doses (27 grams per day), it reduced wrinkles. Both doses were effective at reducing cell death caused by UV radiation [R].
However, in a pilot study of young men (aged 15 to 20), squalene levels are over two-fold higher in those who have acne. This means squalene may increase acne [R].
2) Squalene May Be Anti-Cancer
Doxorubicin is a common chemotherapy drug. In mice, the combination of doxorubicin and squalene increased the anticancer activity of doxorubicin. Squalene increased the accumulation of doxorubicin inside the tumor, targeting the treatment of cancer cells only. It also prolonged the effects of doxorubicin in the body [R].
In mice with pancreatic cancer, squalene improved the accessibility of tumors to therapy. It does so by changing the network of blood vessels that supply the tumor [R].
In mice, the addition of squalene to the skin before exposure to cancerous molecules completely inhibited cancer growth [R].
Squalene increased the anticancer properties of the chemotherapeutic drug doxorubicin in cells [R].
3) Squalene May Help Reduce the Side Effects of Chemotherapy
Cisplatin is a chemotherapy drug that often causes side effects. In mice with intestinal tumors, a combination of squalene-cisplatin prevented the formation of tumors without any signs of toxic side effects [R].
In mice, squalene reduced the DNA damage caused by the chemotherapy drug doxorubicin, especially when squalene was given after doxorubicin [R].
In mice, squalene increased tolerability of doxorubicin 5-fold. It also prevented heart toxicity, which is a common side effect of doxorubicin treatment [R].
4) Squalene is an Antioxidant
In mice, combining squalene with astaxanthin, an antioxidant, lead to higher activation of antioxidant enzymes (SOD1, GPX1), compared to giving either substance alone. Therefore, combining squalene with other antioxidants may increase its antioxidant benefits [R].
In cells, the combination of squalene and other antioxidants (astaxanthin and fucoxanthin/fucoxanthinol) reduced the damaging effect of fats [R].
5) Squalene May Improve Mitochondrial Function
In both young and aged rats, squalene supplementation improved mitochondrial function in the liver by increasing the activities of several energy-producing pathways (Krebs cycle and oxidative phosphorylation) [R].
Squalene also supports detoxing processes in the body (glutathione-dependent) [R].
6) Squalene May Help Fatty Liver Disease
Squalene can help fatty liver disease by increasing fat metabolism (activates PPARα) [R].
Squalene synthase is the enzyme that produces squalene. Mice that do not synthesize squalene (deficient in squalene synthase) show signs of liver dysfunction and abnormal enlargement of the liver (due to increased farnesol production) [R].
However, higher levels of squalene synthesis in mice were linked to increased liver size and dysfunction, along with high cholesterol levels [R].
Therefore, a delicate balance between high and low squalene levels may be beneficial in treating liver dysfunction.
7) Squalene Protects Dopamine Neurons in Parkinson’s
In a mouse model of Parkinson’s disease, squalene, given for 7 days, maintained levels of dopamine in the brain (striatum). It reduced oxidative damage and prevented the toxicity of a chemical that destroys dopamine neurons (6-OHDA) [R].
In flies, both a plant extract (Bougainvillea glabra Choisy) containing squalene and a substance that causes Parkinson’s-like symptoms (paraquat) were given for 4 days. This addition of squalene improved mobility and prevented dopamine loss and cell death [R].
8) Squalene May Improve Response to Vaccines
9) Squalene and Cholesterol
Squalene is a precursor to cholesterol. Whether squalene increases good or bad cholesterol levels is still not understood.
Long-term squalene consumption in humans has not shown a consistent effect on cholesterol levels [R].
However, in 9 long-term hospital patients with heart dysfunction and high cholesterol, squalene given 3 times daily for 7 t0 30 days had no effect on blood levels of triglycerides or total cholesterol [R].
Adding 1 mg of squalene per day for 9 weeks along with rapeseed oil reversed the beneficial effects of rapeseed oil on cholesterol levels, increasing levels of bad cholesterol (VLDL, IDL, LDL) [R].
In 16 healthy men (RCT), a single dose of squalene increased bad cholesterol levels (VLDL) within 9 to 12 hours following consumption [R].
In 13 volunteers, supplementation with shark liver oil, with a content of 3.6g of squalene per day, increased the levels of total cholesterol and reduced the amount of good cholesterol (HDL) relative to total cholesterol [R].
In male mice, though, squalene increased HDL, the “good” cholesterol [R].
However, in rats, blocking squalene reduced bad cholesterol levels (VLDL and triglycerides) [R].
In hamsters, supplementation of both squalene and shark liver oil, which is a known source of squalene, significantly increased levels of total cholesterol in the blood. Squalene also increased triglycerides [R].
Squalene also lowers high cholesterol in liver cells [R].
The effects of squalene on cholesterol levels may be different between humans, animals, and isolated cells. It also may depend on the duration of treatment.
In 50 women taking squalene for 3 months, doses ranging from 13.5 to 27 grams per day caused loose stool. This side effect was minor and temporary [R].
Several cases of squalene-induced, chronic exogenous lipoid pneumonia have been identified. This may be due to the inhalation of squalene particles. This may be a good reason to avoid cooking with olive oil at high temperatures, which contains squalene [R, R, R].
One case of lipoid pneumonia has been linked with ingestion of squalene in the form of shark liver oil [R].
Oral consumption of squalene is relatively safe, considering that squalene is found naturally in food [R].
However, the use of squalene in pregnant women is not recommended because safety has not been evaluated in that population.
- Gulf War Syndrome – symptoms such as fatigue, pain, cognitive dysfunction, insomnia, and mood disturbances
- Pain at the site of injection
- Rash at site of injection
- Hardening of soft tissues
- Muscle pain
- A headache
- General discomfort
- Narcolepsy in children and adults
Therefore, it is possible that direct injection of squalene, even with the other potential benefits that it may play in vaccinations, could still lead to negative effects.
Limitations and Caveats
There are very few human studies that support the benefits of squalene use. Since many of the studies on squalene have been done in cell or animal models, it is difficult to be certain about comparable effects in humans.
No known drug interactions have been claimed for squalene.
The average intake of squalene is estimated to be around 30 mg per day [R].
However, when olive oil plays a more prominent role in the diet, like the Mediterranean diet, levels of squalene can reach anywhere from 200 to 400 mg per day.
Shark liver oil supplements commonly contain between 120 to 500 mg of squalene per dose.
Studies have indicated that squalene supplements are tolerable up to 27 grams with mild side effects [R].
Genetic Variations That May Change Your Response to Squalene Supplementation
Certain genes may increase or decrease your response to squalene supplements.
- FDFT1: This gene codes for the squalene synthase enzyme, which is responsible for the internal synthesis of squalene. Variations in this gene may decrease or increase your natural levels of squalene, which would indicate how effective squalene supplementation will be for you [R].
- SQLE: This gene codes for squalene epoxidase enzyme, which is responsible for breaking down squalene. Variations in this gene may reduce the effectiveness of squalene or increase the amounts in your bloodstream. Higher levels of squalene epoxidase in patients are linked to breast, ovarian, and colorectal cancers [R].
Find out more about how squalene supplements may affect you at SelfDecode.
Pure squalene supplements are not commercially available. Therefore, people use shark liver oil supplements to exploit the benefit of squalene.
One user receiving chemotherapy began using shark liver oil. They claim that the supplement prolonged their lifespan by 3 years and improved quality of life.
This user also claimed the oil was easy to take and digest and caused no side effects.
Another user stated that taking shark liver oil helped resolve a sore throat within one day and caused no side effects.
Multiple users have stated they have had no negative side-effects from taking shark liver oil.