hCG side effects are different for men and women due to the different type of hormone stimulation that the medication can create. hCG is considered a homologue of LH (lutenizing hormone) and so for women hCG stimulates the ovaries, and for men the testicles. The effect of this stimulation is for hCG to slightly increase progesterone and estrogen for women and testosterone for men. The overall increase in hormones from the hCG is generally minor and does not cause any side effects for the general population at the typical 125 IU – 200 IU weight loss dosing.
For women, if the dose of hCG is too high, they may experience cravings (similar to pre-menstrual cravings), breast tenderness, water retention and at most menstrual cycle irregularities (earlier, heavier cycles, sometimes later and lasting longer). These signs of elevated hormones are quickly reversible within a few days of a hCG dose change. When prescribed correctly and based on the individual starting metrics of each patient, the hCG starting dose should completely avoid or minimize the occurrence of these side effects.
Side effects can affect some women with specific preexisting health conditions differently and need to be watched for. Additionally, age and some forms of birth control can also have an impact on the occurrence of side effects, along with some surgical procedures.
We see women on the Mirena or Skyla IUDs, especially in the first 3 years of use having a higher propensity towards side effects (and have a different dosing schedule for them to avoid this). We do not see any side effects or hormone interactions with hCG and Paraguard IUDs or oral birth control pills.
Women on hormone replacement therapy, especially if on progesterone can see an elevation in hormones causing mild breast tenderness and water retention. This is easily corrected with a dose change.
Women with PCOS that have a high-risk history with ovarian cyst rupture may not be approved for hCG due to the risk of ovarian hyper stimulation syndrome (or OHSS). This is one of the most significant potential complications of using hCG where the medication causes an EXISTING ovarian cyst to grow and rupture which requires immediate medical care. Many patients with PCOS are able to use hCG without any problems and the specific history of each patient would inform the clinician to make the appropriate recommendation.
Occasionally preexisting endometriosis and uterine fibroids can be aggravated and cause dysmenorrhea, but this is rare and easily corrected with a dose change.
Having both ovaries removed as part of a hysterectomy or as part of an independent procedure will eliminate the possibility of the hCG being able to increase hormone levels and so will eliminate the side effects related to a change in progesterone or estrogen. The further women are into menopause, the less active and responsive their ovaries are to begin with. For this reason, post-menopausal women (or those with complete hysterectomies) are less likely to see side effects from the hCG.
For men, hCG increases testosterone slightly, which is generally well tolerated. However, in men over 50 their prostate health has to be taken into consideration, along with if they are also taking testosterone replacement therapy. hCG is contraindicated for men with prostate cancer because of the negative effect of an increase in testosterone for that condition.
Due to hCG’s effect on hormone levels in men and women, if patients are getting hormone labs tested or if they are on hormone replacement therapies that include progesterone, estrogen or testosterone then it’s important to know that the lab results can be slightly skewed in some scenarios for patients.
The hCG diet itself has some side effects worth nothing, and this is due to it being ketogenic. In the first week people often experience headaches, fatigue, muscle cramping and can feel tired and lethargic. This is part of a process called ketoadaptation as the body makes some big metabolic changes. Many of these effects are due to the literal lack of fuel (no carbs in the diet, and not enough ketones yet) this is sometimes described as a ‘keto flu’. It effects people very differently, with some noticing nothing, and some people dragging through the first few days. Taking an electrolyte supplement can help a lot as the kidneys tend to waste electrolytes in the early stages of a ketogenic diet, and this can prevent many of the diet related side effects in the first week.