The phrase "although believed" is correct and usable in written English.
It can be used to introduce a contrasting idea or to indicate that something is accepted as true despite potential doubts or contradictions.
Example: "Although believed to be a myth, the legend has persisted through generations."
Alternatives: "even if thought" or "despite being considered".
Although believed to work primarily by repairing the microvasculature, this form of therapy has not been examined in the setting of chronic kidney disease caused by diabetes in which capillary rarefaction plays a pivotal pathogenetic role.
Although believed to be the largest free-standing boulder in the world, Giant Rock, which stands seven storeys tall in the mountainous southern Mojave desert, attracts few tourists, doesn't appear in any guidebook and is an absolute nightmare to get to, requiring a hairy drive over three kilometres of winding dirt roads and hump-backed dunes that feels like a fairground ride from hell.
Certain information in this article has been obtained from third-party sources and, although believed to be reliable, has not been independently verified as to its accuracy, and its completeness cannot be guaranteed.
This highlights that the adsorption of anionic dye, although believed to be primary an electrostatic interaction between the Sn2+ center and the electron rich nitrogen atoms of CR moiety, is rather complicated by many factors other than the surface characteristics of the adsorbent, such as dye dye interaction.
Although believed to play very little part in stability of the atlantooccipital articulation, the posterior atlanto-occipital membrane is important because it is highly visible on MRI assessment and also exhibits some specific anatomical features which may be misinterpreted on imaging as traumatic disruption.
He said he wholeheartedly supported the minimum wage increase, although believed that $9 an hour was probably too low.
(Although, believe me, there were certainly moments).
It's not like you can sell an iOS vulnerability on eBay (although, believe it or not, outlets do exist for such things).
Cambridge, although believing the foul was against them, did not object to the decision.
Although, believe it or not, he still insisted I was insane even after I found him at her house.
Ironically, although believing that rapamycin is dangerous, most scientists do not know the difference between glucose intolerance and IR.
