Homocysteine is an important amino acid for women's health. But its excess can cause serious diseases and complications, including pregnancy.

Homocysteine is a crucial amino acid for women’s health. It is a marker of aging, cardiovascular diseases and disorders of your reproductive system.

You are the whole universe. Are you smiling? The phrase “A woman is a whole universe” has always made me smile. But now I really want you not just to know it, but to realize and feel it.

We consist of billions of cells, each performs the function of a full-fledged living organism. Each of them has a genetic code, like a passport, that determines which galaxy it belongs to and even what it does. Cells are law-abiding and responsible, they diligently perform their specific functions and do not shirk their work. If you create comfortable conditions for them, they are ready to work for a long time and bring benefits. And this is the basis of daily well-being.

Homocysteine гомоцистеїн гомоцистеин

What is homocysteine?

Your body is made of bricks that are produced by the body itself. When food enters the gastrointestinal tract, it is broken down into the simplest substances: glucose and amino acid in particular.

Let’s take homocysteine as an example of how this happens.

Homocysteine is an amino acid that is formed from methionine – an essential amino acid, that is, methionine enters the body only with food. The body itself does not produce essential amino acids, but can only get them with food.

Methionine is found in large quantities in meat and dairy products. Since methionine that has entered the bloodstream from the intestines is foreign to us, the cell simplifies it to homocysteine. Then it can make its own methionine or cysteine from homocysteine. Cysteine can also be used to form an equally important amino acid – taurine. Now from these amino acids the cell can build its proteins and use them for vital activity.


It is important to note that all transformations occur with the help of enzymes, which include vitamins B9, i.e. folic acid, B6 and B12. Without vitamin B9 and B12 homocysteine cannot be converted to methionine, and without B6 cysteine cannot be formed.


In large quantities, homocysteine is toxic to the cell, the excess enters the bloodstream. When the level of this amino acid exceeds the normal plasma concentration (5-12 μmol/l), hyperhomocysteinemia develops. High levels of homocysteine are associated with the risk of increased thrombosis and the development of diseases of the cardiovascular system, neurodegenerative phenomena, obstetric complications, and also reflects the aging process. There are 3 degrees:

  • 30 μmol/L – mild hyperhomocysteinemia
  • 31-100 µmol/l – medium degree
  • over 100 µmol/l – severe degree

But these figures absolutely do not meet the most modern health criteria. As my experience, as well as the experience of my Ukrainian and European colleagues shows, homocysteine values of 9-11 are already dangerous for the female body.

What are the causes of hyperhomocysteinemia?

  • Renal insufficiency;
  • Insufficient intake of vitamins B6, B9, B12 with food;
  • Thyroid diseases, diabetes mellitus, psoriasis and leukemia;
  • Taking certain medications (methotrexate, anticonvulsant, metformin, H2 receptor antagonists, eufiline, etc.);
  • Low physical activity. Therefore, walk at least 10 thousand steps every day!
  • Smoking and alcohol. Here I want to draw your attention that hookah is also smoking, and IQOS, and e-cigarettes, and any “thinnest and lightest” cigarettes;
  • Too much coffee (more than 5 per day). I love coffee and appreciate it for its aroma, taste and treatmnet properties, but everything needs a measure;
  • Genetic disorders of enzyme formation. They are detected by a test called “folate cycle mutations”. It is a very popular analysis, which is now prescribed as a basic one during the examination by nutritionists, but the results cause shock, crazy anxiety and, therefore, stress in the body, which leads to deterioration of health;
  • Long use of COCs (combined oral contraceptives). At this point, I want to note that high homocysteine is not a reason to quit taking contraceptive pills if you do not need an unplanned pregnancy. Abortion is much more harmful for a modern girl. High homocysteine while taking birth control pills is a reason to reconsider your diet!

Thrombosis and cardiovascular pathology

High homocysteine levels damage the inner layer of blood vessels – the endothelium. High-quality endothelium means healthy vessels, and healthy vessels are beautiful skin, bright mind, ability to think and concentrate quickly. It is hard to think with old and leaky endothelium.

гомоцистеїн гомоцистеин Homocysteine

In order to reduce the concentration of homocysteine in the blood, the body uses nitric oxide, if it is not enough, then homocysteine breaks down on its own. It is important to note that during such “self-destruction” aggressive substances are formed that damage the vascular wall.

Studying the effect on the endothelium of mice, it was found that homocysteine causes inflammation, cell death, blood clots in blood vessels, and new cells do not develop properly.

In addition, it stimulates the division of vascular smooth muscle cells and causes them to produce excess collagen. As a result, the vascular wall becomes dense, unable to change its diameter. LDL (low-density lipoprotein), HDL (high-density lipoprotein), cholesterol accumulate in the places of vascular damage.

All these processes lead to the atherosclerotic plaques and vascular aneurysm. If atherosclerosis is determined in the vessels that feed the heart (coronary), then coronary heart disease occurs. The National Health and Nutrition Examination Survey showed that an increase in plasma homocysteine levels is associated with an increased risk of myocardial infarction.

Homocysteine also damages cells, leading to thrombus formation. Beside the direct effect on the endothelium, hyperhomocysteinemia causes platelet activation and aggregation, activation of coagulation factor XII and V and tissue factor, and an increase in thromboxane A2 levels. Other mechanisms are decreased activity of antithrombin III and endogenous heparin (anticoagulant). In this regard, the development of myocardial infarction, stroke, deep vein thrombosis and pulmonary embolism, microcirculatory disorders are possible.

Homocysteine and pregnancy

According to a 10-year study published in Obstetric and gynecology, hyperhomocysteinemia increases the risk of developing such complications during pregnancy:

  • miscarriages;
  • placental insufficiency;
  • intrauterine fetal death;
  • miscarriages at an early stage;
  • preeclampsia and HELLP syndrome;
  • delayed intrauterine growth of the fetus;
  • detachment of a normally located placenta;
  • neural tube defect and congenital heart defects in children;
  • deep vein thrombosis and pulmonary embolism.

I would like to draw your attention to the fact that during pregnancy it is desirable that homocysteine does not exceed 9, not 15.

In the uterus, homocysteine also damages the endothelium and triggers mechanisms that form blood clots inside the vessels. This prevents the attachment of a fertilized egg. The same applies to the formation of the placenta, which is essentially a cluster of blood vessels to nourish the embryo.

It is the disruption of placentation and optimal blood flow between mother and child are possible causes of miscarriage and infertility as a result of embryo implantation defects.

Impaired vascularization of the placenta due to pre-existing endothelial dysfunction or trauma contributes to pre-eclampsia, HELLP syndrome (hemolysis, elevated liver enzymes, low platelet count syndrome), placental abruption, fetal growth retardation and low birth weight.

Due to the effect of hyperhomocysteinemia on thrombosis, complications in the form of deep vein thrombosis or pulmonary embolism in pregnant women are possible.

Given the seriousness of the possible consequences of hyperhomocysteinemia, it is recommended to check the level of homocysteine in all women preparing for pregnancy. It is imperative to check the homocysteine level in patients with previous obstetric complications and in women whose relatives had strokes, heart attacks and thrombosis at the age of 45-50 years.

Brain and neurodegenerative diseases

Normally, there is a barrier between the brain and the blood vessels of the body, through which substances necessary for the vital activity of neurons selectively penetrate. In hyperhomocysteinemia, the functioning of this barrier changes. When the barrier becomes permeable, homocysteine has a neurotoxic effect, activating NMDA receptors that promote the accumulation of calcium and reactive oxygen species, which in high concentrations lead to cell damage.

There is an increased risk of white matter damage, cognitive impairment, brain atrophy and dementia. In a mouse model, hyperhomocysteinemia has been shown to enhance the formation of β-amyloid plaques, a process associated with the onset of Alzheimer’s disease.

High homocysteine levels in both plasma and cerebrospinal fluid explain cognitive decline and depression in patients with Parkinson’s disease

It is a progressive neurological disorder. It strongly affects movement, and more than 3-5% of the US population aged 65 and older suffer from this pathology. Clinically, this disease is manifested by tremor at rest, muscle rigidity. In Parkinson’s disease there is damage in the dopaminergic neurons of the substantia nigra, this is a hallmark of the disease.


An urgent and widespread problem is the obvious link between hyperhomocysteinemia and stroke, which is associated with increased thrombosis. In people who have had a stroke, the blood supply to the brain is interrupted, leading to the death of nerve cells and loss of function in certain areas of the brain, and this is due to a lack of oxygen and nutrients.

Homocysteine and osteoporosis

High homocysteine levels increase the activity of osteoclasts (cells that destroy bone tissue). The situation is aggravated by decreased blood supply to the bone, stimulation of atherogenic processes, platelet adhesion and, as a result, osteoporotic fractures due to changes in the biomechanical properties of the bone.

Marker of aging

With age, the amount of homocysteine in the blood always increases – the cells are less active, and the kidneys work worse, which means that the excretion in the urine is not as effective. The concentration of homocysteine increases, and with it the risk of cardiovascular disease (by 30%), especially coronary heart disease (by 50%), as well as cognitive diseases, depression and dementia, and decreased bone mineral density.

This analysis took into account an increase in homocysteine level by 5 μmol/L, which is considered a mild degree of hyperhomocysteinemia.

Of course, the risk of developing these diseases is influenced by other factors: age, lifestyle, kidney health, genetics. Homocysteine in this case worsens the prognosis.

I tell in detail about the lifestyle, the basic rules of self-care and practical recommendations for maintaining your health in my course “All About You: How to be a Woman“.


The level of homocysteine in the blood depends on a sufficient amount of enzymes involved in the reactions of methionine and cysteine formation. That’s why the balance of vitamins B6, B9 and B12 in the body is important.

The Nurses Health Study notes that dietary intake of less than 3 mg of B6 per day or less than 350 mg of folic acid per day significantly increases the risk of cardiovascular and neurodegenerative diseases.

It is important to consider that the body’s need for vitamin therapy also depends on genetic characteristics, age, gender, activity level and metabolic status, as well as plasma nutrient levels. Therefore, it is necessary to monitor the level of homocysteine and consult with your doctor about taking certain nutritional supplements.

Be healthy mentally, physically, sexually and reproductively!

Please share this article on your social networks, let as many people as possible know the simple things that save life and make it better, and therefore happier!

💗 to everybody

With love, your Natalia Silina,
doctor of gynecologist-endocrinologist,
UNICEF and UNFPA expert on sexuality education

You can learn how to properly prepare for pregnancy in my course Preparing for Pregnancy. And everything you need to know about pregnancy and the first year of the baby you will find in the course Pregnancy and postpartum – a complete guide.

I’m eager to file all of these courses in English, just send me a request to dr.silinaeducation@gmail.com

You can always choose your doctor at the Lior Medical Center.


  1. O Fridman. Hyperhomocysteinemia: atherothrombosis and neurotoxicity. Acta Physiol Pharmacol Ther Latinoam, 1999
  2. Kilmer S McCully. Homocysteine And Heart Disease. US Cardiology, 2004
  3. Hui Cao, Xinhua Hu. Homocysteine Level and Risk of Abdominal Aortic Aneurysm: A Meta-Analysis. PLOS One, 2014
  4. Avinash Kumar, Henry A. Palfrey. The metabolism and significance of homocysteine in nutrition and health. Nutrition & Metabolism, 2017
  5. Paul Ganguly, Sreyoshi Fatima Alam. Role of homocysteine in the development of cardiovascular disease. Nutrition Journal, 2015
  6. Steegers-Theunissen, Régine P. PhD. The role of maternal homocysteine concentration in placenta-mediated complications: findings from the Ottawa and Kingston birth cohort. BMC Pregnancy and Childbirth, 2019
  7. Elena Azzini, Angela Polito. Homocysteine: Its Possible Emerging Role in At-Risk Population Groups.  International Journal of Molecular Sciences, 2020


  • Раджу прочитати