Progesterone is a hormone that is produced by the gonads and the adrenal glands. Although progesterone is sometimes assumed to be a “female” hormone, it is actually produced by people of all sexes in varying amounts. As part of feminising hormone treatment, progesterone can promote breast development and help to suppress testosterone (Bahr et al., 2023; Prior, 2019). Hence, many trans women choose to take progesterone as part of their feminising hormone treatment.
However, some progesterone preparations contain bovine gelatine, which is unsuitable for vegans and vegetarians. Other progesterone preparations contain lactose, which may be acceptable for vegetarians but is unsuitable for vegans. This article covers the different preparations of progesterone and whether they are suitable for vegans and vegetarians.
Chemically, there are two main kinds of progesterone. Bioidentical progesterone is chemically the same as the progesterone produced by the body. Synthetic progestin is a form of progesterone made in the laboratory which is chemically different from the progesterone produced by the body. Bioidentical progesterone is usually recommended for feminising hormone treatment, because it has much medical risks than synthetic progestin. There is some evidence that synthetic progestin can be associated with increased risks of blood clots and breast cancer, whereas bioidentical progesterone is not associated with these risks (Asi et al., 2016; Fournier et al., 2008; Scarabin, 2018).
However, the most commonly prescribed form of bioidentical progesterone, Utrogestan®, contains bovine gelatine, and so is unsuitable for vegans and vegetarians.
If you are vegan and want to take bioidentical progesterone, there is a pessary called Cyclogest® and a vaginal gel called Crinone®, which do not contain any products from animals. These can be applied rectally.
If you are vegetarian and would prefer to take progesterone as an oral preparation, the synthetic progestin Provera® is a potential option. This does not contain bovine gelatine, and so may be acceptable for vegetarians. However, it does contain lactose, and so is unsuitable for vegans.
Another important consideration here concerns the increased medical risks associated with synthetic progestin, specifically blood clots and breast cancer.
Regarding blood clots, research suggests that trans women who are receiving feminising hormone treatment have a higher lifetime risk of thromboembolic disease than the general population (Getahun et al., 2018; Streed et al., 2017). Research also suggests that cis women who are taking combined oral contraceptives containing synthetic progestin have an increased lifetime risk of thromboembolic disease (Vinogradova et al., 2015).
Regarding breast cancer, a recent cohort study showed that trans women who are receiving feminising hormone treatment have a lifetime risk of breast cancer that is higher than the lifetime risk for cis men but lower than the lifetime risk for cis women (de Blok et al., 2019). For reference, the lifetime risk for cis women is approximately 12%, while the lifetime risk for cis men is approximately 0.1% (Sonnenblick et al., 2018). Studies on postmenopausal cis women have also suggested that hormone replacement therapy containing synthetic progestin is associated with an increased risk of breast cancer (Beral, 2003; Colditz et al., 1995; Rossouw et al., 2002).
Given the above, synthetic progestin is not the recommended option if you have a personal history or a strong family history of blood clots or breast cancer. If you do wish to proceed with synthetic progestin, then it is important that you understand the above medical risks.
The table below summarises the different progesterone preparations and whether they are suitable for vegans and vegetarians.
| Preparation | Type | Route | Suitable for Vegans | Suitable for Vegetarians |
| Utrogestan® | Bioidentical | Oral tablet | No | No |
| Crinone® | Bioidentical | Rectal gel | Yes | Yes |
| Cyclogest® | Bioidentical | Pessary | Yes | Yes |
| Lutigest® | Bioidentical | Pessary | No | Yes |
| Provera® | Synthetic | Oral tablet | No | Yes |
| Norethisterone® | Synthetic | Oral tablet | No | Yes |
Asi, N., Mohammed, K., Haydour, Q., Gionfriddo, M. R., Vargas, O. L., Prokop, L. J., Faubion, S. S., and Murad, M. H. (2016). “Progesterone vs. Synthetic Progestins and the Risk of Breast Cancer: A Systematic Review and Meta-Analysis”. Systematic Reviews, 5 (1): 121.
Bahr, C., Ewald, J., Dragovich, R., and Gothard, M. D. (2023). “Effects of Progesterone on Gender Affirmation Outcomes as Part of Feminizing Hormone Therapy”. Journal of the American Pharmacists Association, online before print.
Beral, V. (2003). “Breast Cancer and Hormone Replacement Therapy in the Million Women Study”. Lancet, 362 (9382): 419–427.
Colditz, G. A., Hankinson, S. E., Hunter, D. J., Willett, W. C., Manson, J. E., Stampfer, M. J., Hennekens, C., Rosner, B., and Speizer, F. E. (1995). “The Use of Estrogens and Progestins and the Risk of Breast Cancer in Postmenopausal Women”. New England Journal of Medicine, 332 (24): 1589–1593.
de Blok, C. J. M., Wiepjes, C. M., Nota, N. M., van Engelen, K., Adank, M. A., Dreijerink, K. M. A., Barbé, E., Konings, I. R. H. M., and den Heijer, M. (2019). “Breast Cancer Risk in Transgender People Receiving Hormone Treatment: Nationwide Cohort Study in the Netherlands”. British Medical Journal, 365: 1652.
Fournier, A., Berrino, F., and Clavel-Chapelon, F. (2008). “Unequal Risks for Breast Cancer Associated with Different Hormone Replacement Therapies: Results from the E3N Cohort Study”. Breast Cancer Research and Treatment, 107 (1): 103–111.
Getahun, D., Nash, R., Flanders, W. D., Baird, T. C., Becerra-Culqui, T. A., Cromwell, L., Hunkeler, E., Lash, T. L., Millman, A., Quinn, V. P., Robinson, B., Roblin, D., Silverberg, M. J., Safer, J., Slovis, J., Tangpricha, V., and Goodman, M. (2018). “Cross-Sex Hormones and Acute Cardiovascular Events in Transgender Persons: A Cohort Study”. Annals of Internal Medicine, 169 (4):205–213.
Hitchcock, C. L., Elliott, T. G., Norman, E. G., Stajic, V., Teede, H., and Prior, J. C. (2012). “Hot Flushes and Night Sweats Differ in Associations with Cardiovascular Markers in Healthy Early Postmenopausal Women”. Menopause, 19 (11): 1208–1214.
Mather, K. J., Norman, E. G., Prior, J. C., and Elliott, T. G. (2000). “Preserved Forearm Endothelial Responses with Acute Exposure to Progesterone: A Randomized Cross-Over Trial of 17-Beta Estradiol, Progesterone, and 17-Beta Estradiol with Progesterone in Healthy Menopausal Women”. Journal of Clinical Endocrinology and Metabolism, 85 (12): 4644–4649.
Prior, J. C. (2019). “Progesterone Is Important for Transgender Women’s Therapy-Applying Evidence for the Benefits of Progesterone in Ciswomen”. Journal of Clinical Endocrinology and Metabolism, 104 (4): 1181–1186
Rossouw, J. E., Anderson, G. L., Prentice, R. L., LaCroix, A. Z., Kooperberg, C., Stefanick, M. L., Jackson, R. D., Beresford, S. A., Howard, B. V., Johnson, K. C., Kotchen, J. M., and Ockene, J. (2002). “Risks and Benefits of Estrogen Plus Progestin in Healthy Postmenopausal Women: Principal Results from the Women’s Health Initiative Randomized Controlled Trial”. Journal of the American Medical Association, 288 (3): 321–333.
Scarabin, P. Y. (2018). “Progestogens and Venous Thromboembolism in Menopausal Women: An Updated Oral Versus Transdermal Estrogen Meta-Analysis”. Climacteric, 21 (4): 341–345.
Sonnenblick, E. B., Shah, A. D., Goldstein, Z., and Reisman, T. (2018). “Breast Imaging of Transgender Individuals: A Review”. Current Radiology Reports, 6: 1.
Streed, C. G. Jr, Harfouch, O., Marvel, F., Blumenthal, R. S., Martin, S. S., and Mukherjee, M. (2017). “Cardiovascular Disease Among Transgender Adults Receiving Hormone Therapy: A Narrative Review”. Annals of Internal Medicine, 167 (4): 256–267.
Vinogradova, Y., Coupland, C., and Hippisley‐Cox, J. (2015). “Use of Combined Oral Contraceptives and Risk of Venous Thromboembolism: Nested Case‐Control Studies Using the QResearch and CPRD Databases”. British Medical Journal, 350: h2135.