Levothyroxine is commonly used to treat hypothyroidism. This study investigates how far the intake of L-T4 influences body composition, energy expenditure, respiratory quotient as well as strength, endurance and mobility in premenopausal women who suffer from subclinical hypothyroidism. Twenty-five women (27.36±5.77 years) with subclinical hypothyroidism were included in the study. The intake of levothyroxine was assumed. Subjects were examined immediately after study inclusion, after two months of levothyroxine use, and after TSH was fully adjusted to the reference range. In all measurements TSH, fT3 and fT4 were determined, body weight, body composition, energy expenditure and the respiratory quotient were measured, and a test battery was performed to identify strength, mobility and endurance capacity. TSH decreased from 5.95±0.99 μIU/ml at study inclusion to 1.2±0.33 μIU/ml after final trial. No change in weight, BMI, muscle mass, fat mass, energy expenditure and respiratory quotient was observed (p>0.05). A significant improvement in chest press (p=0.002), leg extension (p<0.001), right-hand grip strength (p=0.009) shoulder mobility (p<0.001), hip mobility (p=0.07), explosive strength (p=0.041) and the anaerobic threshold (p=0.13) was identified. Likewise, a non-significant (p=0.298) increase in left-hand grip strength could be detected.In summary, although levothyroxine does not positively affect body composition, energy expenditure and respiratory quotient, it can improve strength, mobility and endurance performance. For this reason, treatment with levothyroxine is recommended to improve exercise capacity in subclinical hypothyroidism.

Menopause is for many females associated with an occurrence of a variety of health complaints and a decrease in quality in life. Hot flashes, sleep disturbances and a variety of other symptoms result in a strong psychological strain. Hormone replacement therapy for treatment of climacteric complaints is discussed controversially regarding associated side effects. This is a major reason to propose treatment with plant derived extracts and compounds as an alternative. Such compounds are available either as drugs but mostly as nutritional supplements. Here we have to distinguish between so-called phytoestrogens which are postulated to act via estrogen receptors such as hop extracts, soy extracts, pomegranate extracts and red clover extracts. A second group of compounds addresses postmenopausal complaints independent of estrogen receptors. This group includes yams, actaea racemosa, agnus castus, rhei radix extracts and spinach extracts. For none of the mentioned substances and extracts could a clear proven effectiveness for the treatment of postmenopausal complaints be demonstrated. In contrast, for some of the mentioned substances, for example isoflavones, there are concerns regarding side effects and safety. The free availability of such nutritional supplements results in an uncontrolled consumption. Different products were combined and consumed in doses far higher than recommend by the manufacturers.

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