Other things that may indicate you could benefit from testosterone include depression, lethargy, and general weakness. Women have said their thoughts seem clearer after adding testosterone. Testosterone boosts muscle mass and strength.
On the other hand, because of its risks, there is not a free lunch involved in using testosterone as some sort of legal pick-me-up or counter to the normal effects of aging. If you're feeling draggy on the initial estrogen HRT you try and the first thing your doctor suggests is perking you up with testosterone, you might want to think about that strategy just a bit: using one hormone to patch inadequacies in a maladjusted other is not actually a sound or desirable approach. In fact, the American Association of Clinical Endocrinologists Medical Guidelines for Clinical Practice for the Diagnosis and Treatment of Menopause (free signup required to read) specifically states that we can't even determine whether or not we need to supplement other hormones until we have fine-tuned our estrogen to meet our needs as closely as possible.
The truth is that many of the results attributable to testosterone supplementation are more likely to be from better-tuned estrogen supplies, and we're just using our testosterone to augment our estrogen hrt (because of the interconversion that can and does happen when estrogen needs are unmet). And that's at a fairly substantial metabolic cost. So waiting until we know it's really testosterone we need is the first key to identifying unmet testosterone needs.
Aggression, snappiness, anger, frustration, impatience—all of these signs of exaggerated mood may be due to excessively high levels of testosterone.
Masculine characteristics such as deeper or coarser voice, clitoral enlargement, and breast shrinking are signs of excess testosterone. Male hair growth patterns—more or thicker hair on the face and breasts but loss from the top of the head and at the hairline—are typical of testosterone imbalance.
Changes caused by testosterone often mimic those of adolescence (try to hold the jokes down to a low roar, ladies). Greasy skin and hair and acne or pimples are often the very first signs you see of a high testosterone level.
Finally, weight gain and fluid retention are seen at high levels. This needs to be distinguished from muscle and bone mass enhancement that are seen at therapeutic levels, however, and because of the overlap with estrogen effects, may require looking closely at both hormones.